rjp1: calculate sample length correctly
|Reported by:||fuzzie||Owned by:||fingolfin|
This fixes the RJP1 player to use the correct sample length - the length entry in the file is actually "length after provided position", it seems.
I couldn't find any specs, but I looked at the m68k player source I could find for the format, made this patch based on what it seemed it was doing, and then thought to check the start/end offsets within the data: they match the reasoning of this patch (i.e. the sample data is packed together if at this length) and the data seems correct, so I'm pretty sure this is correct.
This fixes bug 3001110, which was due to an assert since the playback was starting after the supposed end of samples. Patch against trunk.
Ticket imported from: #3006178. Ticket imported from: patches/1293.